Agree that 500 for a barfine is expensive, but some bars in Soi Tiger have a higher barfine than that. If I remember the name correct, there is a bar in soi Tiger called "Cheeky bar", and there the barfine was 1000...
atleast it was 1000 for the ones that where dancers. I had a girl from that bar and she said directly that "Dont pay barfine" come get me after work instead...
Also I had one girl from a bar were the barfine was 500, and it was like 2AM, so I told her that I would wait instead for the bar to close, then she just told me that she would go down 500 in price for LT, if I paid barfine. But if she gets like 50% of the barfine back, then it not so strange when you think about it...